Storage battery.



F. WRIGHT.

STORAGE BATTERY.

APPLICATION FILED JAN. 9. 1914.

RENEWED FEB. 6.1918.

Patented Sept. 24, 1918.

subjected ,to the burning 'rnnnnmor. ware or rouenxnnrsm, new YORK, nssrenon, n'Y' 'mnsnn ASSIGN- JMENTS, T0 WRIGHT STORAGE BATTERY COMPANY, OF PQUGHKEEPSIE, NEW YORK,

A oonrona'rxoiv or new roan Application filed January 9, 1914, s rial No. v$11,150

To all whom it may concern:

Be it known th a citizen of the United States, residing at Poughkeepsie, county of Dutchess, State of New York,'have invented certain new and useful Improvements inStorafi B g -Egg 3 m to and I do hereby declare the fo a full, clear, and exact description of the invention, such as. will enable. others 'sk1lled 'in the art to which it appertaina to make object of the present'invention to provide electrodes substantially freefrom shedding and sulfating, and" particularly adapted'for mounting close together;

To obtain the above enumerated and other objects arising from 21 1 improvements here disclosed, the active material used for pasting the grids iscompounded in special manner and before the forming treatment is or strengthenin action of concentrated sulfuric acid whic is painted on in small quantity and produces a marked change in the active material and special beneficial effects as hereinafter recited, and in addition to this the plates after forming are subjected to a surface treatment whereby dead or rotten material is removed from the faces of each plate, leaving the plates clean and firm, with their active material directly exposed to the electrolyte and in best condition and position for efiicient operation at high discharge rates. This surface treatment which need be nothing more than a milling operation for the removal of a layer of about one sixty-fourth (1/64) of an inch thick has a marked influence on the tendency of the plates to shed or sulfate, and practically eliminates both of these factors.

The details of the invention and special objects and advantages are made clear by the following detailed description, which is to be taken in conjunction with the accompanying drawings, wherein- Figure 1 is a side view of a plate after sromen BATTERY.

Spmzification of Letters l 'atent.

at I, FREDERICK WRIGHT,-

lead-antimony' with about 5% I v 7 desired. Each 'grid, as the present invention ftions'by vertical ribs 3 Fig. 2).

rising slightly above intersected vertical ribs 3. The bars 2 of these bars 2 about in the Renewed February 6, 1918. Serial No; 215,781.

forming, and before removal ofthe surfacev layer F ig'.

'. removal of the surface layer, and

. Fig; 3 is a perspective view of a corner of one of the grids before it is filled in with the active material paste.

2 is a" view of the same plate after I Patented se aaa, 191s.

The grids usedby me are-preferably of antimony an maybe cast with pressureor without, as indicated in Fig.- 3-, comprises a frame 1 sub-divided into secing acrossthe frame an the vertical ribs are two groups of transverse retaining'bars 2 each oftriangular cross-section with the d to,

Ext'endflat side of the triangle facing inward and the apex-of the triangle the'outer edge of the the series on one side of the grid are staggered with respect to those on the other side of the grid to form-recesses or pockets forthe reception of the active material. Small lugs 2 may be cast integral with relation indicated in Figs. 2 and, 3, and the material of these lugs may even extend through from one triangular bar to its opposing bar, thereby bracing the bars between the vertical ribs 3 and also assisting in the retention of the active material within the pockets formed by the triangular bars. This configuration of grid is satisfactory, but other shapes may be used. Preferably the frame at the topof section proportional to the amount of current whichis to be carried at any particular point along its length.

facing outward and The active material for the positive plate I is made up of equal parts by weight of battery lead and red lead. Battery analyses furnished by manufacturers 1s a composition substantially as follows; true lead is a standard article on the market, and may bepurchased under'that name from red lead 80%; litharge 19%, insoluble material, such as silica, iron and silver, 1%.

eration may be performed by hand, the

paste of active material being worked into the pockets bymeans of a trowel.

The active mixture for the negative late preferably consists of battery lead a one, wet with dilute acid, and put into the pockets or recesses as above recited.

7 After the grids are filled with active material, they, are laid aside and allowed to dry. Preferably, this drying is carried on at room'temperature, the plates being exposed to free circulation of air until they.

look dry. This ordinarily takes from two days to a Week, depending somewhat on atmospheric conditions.

The next step in the production of the bat tery. is an important one, and consists in painting the pasted plates with concentrated sulfuric acid. The operation is car-' ried out with commercially concentrated sulfuric acid which has a specific grayity of about 1.78 {66 Baum). lhis acid may be applied with a bristle brush, say one and onehalf inches Wide, and is put on quickly, the brush being merely dipped in the acid and wiped back and forth across the plate until all parts of the surface have been. wet with the strong acid. 'Ordinarily, the brush is not passed more than once over any particular' portion of the plate area. The concern trated acid soaks into the dry plates very quickly, apparently penetrating to all parts of the active material, but certainly having a very great effect on the outermost parts. Theacid seems to burn or density the active material, and without speculating as to the, chemical or molecular changes which may] have been brought about, it is suiiicient to here recite some of the apparent physical effects. The plates, immediately on painting with the strong acid, turn to a dark Indian when the plates are again dried. A surface hardening is produced and'the active material becomes densified into a solid cake. The plates ring like metal when struck a blow and electrically they are much better con- I ductors than before the painting with acid.

ullso, when the plates are subjected to the subsequent forming treatment, the beneficial effects of the painting are readlly apparent, the plates forming more quickly and. more 7 supporting grid. The plates are then rea thickness throughout. brown, though this color disappears in part I uaraaos completely, and apparently affording better conductivity to the flow of current, particularly at the earlier stages of the forming operation. In general, it has been my experience that plates so painted can be formed jars with rubber separators between, andv there charged for several hours at a current of about of the normal eight hour rate for the particular plates under treatment, and in sulfuric acid of a specific gravity of about 1.15,?Ztl'lfl after this has continued for, say, three hours, the charging rate is increased to of the normal eight hour rate until the voltage at this rate volts per cell. The cells are then discharged at 86% of the normal eight hour rate until the voltage per cells drops to 1.67. @rdinarily, one charge and discharge is suflicient to completely form the plates, though the treatment may lee-repeated two orthree times if such procedure in any particular case be necessary or desirable. The formed plates are then taken out of the acid and washed in water and dried in air. -They are then of the general appearance indicated in Fig. l, the active material having swollen somewhat and bulg'gingfrom the, pockets a very little and presenting a somewhat uneven surface and a somewhat uneven outline for the for the next and very important step, whereby athin surface layer is removed from both sides of the plate, and the plate is in large measure insured against subsequent shedding and sulfating.

The removal of the surface layer may be conveniently effected in a milling machine. The formed plate is clamped to a flat surface and a broad milling cutter removes a layer about one-sixty-feurth .(l/fi l) of an inch thick. The material so removed in cludes the dead or rotten surface layer of the active material and also takes a'little from the face of the grid, leaving the grid sharply defined, as indicated in Fig, 2, and clean on the exposed areas, and of uniform largely to a high Weight efficiency and per mits the plates to be mounted very close together, thereby decreasing the internal resistance of thebattery when in normal use, and contributing to a high rate of discharge.

After the trimming or surfacing opera tion, the plates are assembled and burned into their terminal connectors and are equipped with wood separators of suitable character, and then assembled in jars of orlhis surface trim- I ming of dead or inactive material contributes I They dinary construction and provided with fresh sulfuric acid of a specific gravity of 1.150. are then charged at normal rate, or a little above, until theacid reaches a specific about twelve hours at the normal rate. rdinarily this charging operation need not be'repeated, but the for use after the first charging. On open tially free from ing,

the active materlal and facilitate voltagefor a group of three be about sixand one-half voltsf,

circuit, the cells should and the discharge rate, while varying,

course, with the size of the plates, is rela-v tively high incomparison withother lead batteries of comparable weight and cost.

It is a particular even at very high rates of discharge, there will be found in the bottom of the cell very little mud or other evidence of shedding or disintegration of the plates,

and the plates themselves will be substaninjurious 'sulfating. These characteristics I attribute very largely to the trimming operation which follows the forming, and whereby the dead or exwith concentrated sulfuric acid to densify the subsequent fornnng operation.

2. The method of treating a lead storage battery plate after pasting and before forma ing, which consists in thoroughly drying the pasted plate and then subjecting it to the densifying action of sulfuric acid of about specific gravity 1.7 8 applied in. small quantity to the face of the plate andallowed to penetrate into the interior.

.lead storage battery plate,

gravity of 1.29 to 1.31, which may be in battery will be ready dilute sulfuric acid, then drying plates at room temperature and before form-' characteristic of the 5. A step inbatteries heredisclo sed that after operating for a long time,

does not remain to to a depth of '3. The method of densifying a pasted which consists in quickly brushing it over with sulfuric acid of about specific gravity 1.7 8. 4:. The method of making a lead stora e. battery plate, which consists in pasting t .8 grid with a mixture of equal parts by weight of battery lead and-red lead moistened with the pasted ing the same 'palnting them over lightly with but a small quantity of concentrated sulfuric acid to densify and harden the active 'material and facilitate treatment.

storage battery plates, which consists in the mechanical removel of the surface layer of the active material and of the grid after electrolytic forming. and before assembly of the plate in abattery. a

6. The method of treating an electrolytically formed battery plate to reduce shedthe forming the manufacture of lead ding and 'sulfating, which consists in me-.

chanically removing a layer of material;

about one sixty-fourth of an inch thick from both sides of the plate, thereby-removing the dead or inactive material ofthe grid and its filling and leaving a compact dense and uniform plate free fromloosely supported surface-material. "1 I '7. The method of making lead storage battery plates which grids with a, mixture of'battery lead and red lead moistened with dilute sulfuric acid,

consists in pasting the drying gradually, painting with concentrated sulfuric. acid to densify the active material, forming electrolytically with cur the dead or in-" rent and then milling away active material from the surface of the id inch. lntestimony whereof I aflix my signature, in presence of two witnesses.

Witnesses:

ALFRED BOLOGNESI,

S. BLIDE.

FEEDER CK WRIGHTQ 

